The present invention relates to a cleaning device for a heat exchanger which removes mold, germs and the like attached to an outer surface of the heat exchanger.
Heretofore, in a heat exchanger, for example, a heat exchanger which functions as an evaporator constituting a refrigerant cycle of an air conditioner, a refrigerant in the heat exchanger absorbs heat from surrounding air and consequently it evaporates, whereby a cooling function is exerted to cool a space to be cooled. In this case, when the refrigerant absorbs the heat from the surrounding air, water in the air condenses (dew-condenses) and attaches to the surface (the outer surface) of the heat exchanger in the form of water droplets. During operation, the water which attaches to the outer surface of the evaporator gradually grows and then drops down owing to a gravity, whereby the water is discharged therefrom. After the operation is stopped, however, the water remains on the outer surface of the heat exchanger. The water includes dust and microorganisms such as bacteria in the air, and when they remain on the outer surface of the heat exchanger, they are deposited as the mold and dust on the outer surface of the heat exchanger.
In a case where the operation is performed in a state in which the mold and dust are deposited on the outer surface of the heat exchanger in this manner, the mold and dust deposited on the heat exchanger disadvantageously emit odor into the space to be cooled, whereby the space to be cooled is contaminated. Therefore, the heat exchanger has heretofore been cleaned to remove the dust and microorganisms such as bacteria attached to the outer surface of the heat exchanger.
Specifically, an ozone producer which produces gas-phase ozone from the air is disposed. After a cooling operation ends, the gas-phase ozone produced by the ozone producer is formed into micro bubbles, and dissolved in the water to produce ozone water (ozone-containing water). Then, this ozone water is supplied to the outer surface of the heat exchanger to destroy the microorganisms with the ozone water (e.g., see Japanese Patent Application Laid-Open No. 5-39932).
However, in a case where the ozone is produced from the air by the ozone producer as described above, a problem occurs that nitrogen oxide (NOx) known as one of causative substances of atmospheric contamination is also produced in a process of the production of the ozone. Furthermore, the gas-phase ozone is produced from the air, and this ozone is dissolved to produce the ozone water, so that a concentration of the ozone water cannot sufficiently be raised.